Variable speed transmission



Aug. 22, 1939. o. H. BANKER VARIABLE SPEED TRANSMISSION Filed Aug. 2,1954 2 Sheets-Sheet 1 Q \N. r k Q Q m mm 3 I 1 D 3 hwi aww n m 4 iv m Hmm Emm mwwawfiwwwwmwm A7 474/ m \uk \MW. ll 3 3 Q. 8 mm wb Q mw k m v onmm Q. m Q om Q 9 H Q N mx IROQIW 06 a. HBczrz/(ez;

Aug. 1939- o. H. BANKER VARIABLE SPEED TRANSMISSION Filed Aug. 2, 1954 2Sheets-Sheet 2 fi Q 0500/12? Ban/16f;

\ i l i Patented Aug. 22, 1939 UNITED STATES' PATENT OFFICE VARIABLESPEED TRAN SIVIISSION tion of Delaware Application August 2, 1934,Serial No. 738,127

Claims This invention has to do with variable speed transmissions, foruse in automobiles, trucks, buses, railway cars and other places where amuliplication of torque is required in starting or in overcomingincreased resistance, and is particularly concerned with a transmissionof novel design in which the velocity of a rapidly circulating liquid isemployed as the means for bringing the driven shaft up to a speed whereit can be handled efliciently by the driving shaft in a direct drivewithout further multiplication of torque.

The purpose of the invention is to provide an improved transmission ofthe character described in which the driven shaft, when caused by theaction of the liquid system to be brought upto 'the speed at which adirect drive can properly be undertaken, will become automaticallycoupled up with the driving shaft in a positive oneto-one ratio upon amomentary deceleration of the driving shaft.

While the foregoing statement is indicative in a general Way of thenature of the invention, other more specific objects and advantages willbe apparent to those skilled in the art upon a full understanding of theconstruction, arrangement and operation of the new transmission.

A preferred embodiment of the invention is presented herein by Way ofexemplification, but it will of course be appreciated that the inventionmay be incorporated in other structurally modified forms coming equallywithin the scope of the appended claims.

In the accompanying drawings:

Fig. 1 is a vertical longitudinal section through a transmissionconstructed in accordance with the invention;

Fig. 2 is a schematic view illustrating the principle on which thehydraulic torque converter in the transmission operates.

Fig. 3 is a fragmentary section through the direct-drive clutch in thetransmission, taken on the right angular line 3-3 of Fig. 4, showing theclutch in full lines energized but still disengaged owing to adifierence in the speeds of the driving and driven shafts, and showingthe clutch in dotted lines fully engaged;

Fig. 4 is a section through the transmission at the location of thedirect-drive clutch, taken on the line 4-4 of Fig. 3;

Fig. 5 is a detail view of one of the teeth of the clutch; and

Fig. 6 is a section through the transmission at the location of theoverrunning brake, taken on the line 6-6 of Fig. 1.

The transmission which is shown in the drawings is enclosed within acasing III which is at tached by bolts H to the rear end of the crankcase l2 of an internal combustion engine. A shaft l3which is the drivenshaft of the transmissionextends the full length of the casing I 0, withits front end journaled in bearings l4 in a bore in the center of thefly wheel l5 of the engine, and with its other end journaled in bearingsIt in the rear end of the casing. The shaft 10 I3 terminates beyond therear end of the casing in a coupling flange ll.

A tubular shaft I8which is the driving shaft of the transmission-isjournaled on the shaft l3 near the front end of the latter and isconnected to the fly wheel l5 by means of a plate l9 and a collar 20.The outer edge of the plate I9 is attached by bolts 2! to the rim of thefly wheel i5, while the inner edge of the plate is attached by bolts 22to a flange on the collar 20. The collar is splined on the front end ofthe shaft it.

Another tubular shaft 23 is journaled on the driven shaft [3 back of thedriving shaft 18 and is provided at its rear end with an axiallyshiftable but non-rotatable collar 24. When the collar 24 is shiftedrearwardly, a set of outwardly projecting clutch teeth 25 on the rearend of the same will move into circumferentially interlocked associationwith a complementary set of clutch teeth 26 on the inside of a gear 21which is secured to the shaft l3, whereupon the shaft 23 will beconnected with the driven shaft l3 for movement as a unit with thelatter. When the collar 24 is shifted forwardly, from the neutralposition shown in Fig. 1, a gear'28 which is formed on the periphery ofthe collar will move into mesh with a gear 29 on a countershaft 30. Asthe gear 29 is in mesh at all times with a gear 3| on a secondcountershaft 32, and another gear 33 on the countershaft 32 is in meshat all times with the previously mentioned gear 21 on the driven shaftl3, a reverse drive connection between the shafts 23 and I3 willthereupon be established.

The collar 24 is adapted to be moved either rearwardly or forwardly fromits neutral position by a shifting fork 34, which fork is secured to arock shaft 35 and is connected by suitable linkage (not shown) to a.conveniently located hand or foot control lever. I

The liquid system within the transmission acts between the driving shaftl8 and the intermediate shaft 23, which latter shaft when clutched tothe .driven shaft [3 by the collar 24 may be considered as a part of thedriven shaft. The liquid used, which is preferably a light oil,circulates through passages which are formed between curved blades onthree inter-nested turbine wheels 36, 31 and 38. The wheel 36, which iscomposed of an annular series of blades 39, is the centrifugal impellerof the assembly and is attached rigidly to the rear end of the drivingshaft I8. The second wheel 31, which is provided with four separate butrigidly associated series of blades fill, M, 42 and E3, is attached tothe front end ofthe shaft 23. The third wheel 38, which is provided withthree separate but rigidly associated series of blades 46, 35 and 66,fits about both of the other wheels 36 and 3?, in the form of aninwardly opening annular housing. The wheel 38 is attached at its frontedge to a short sleeve t? which is journaled on the shaft 58 in bearings38, and is attached at its rear edge to another sleeve d9 which isjournaled on the shaft 23 in bearings 58. The sleeve ll is alsorotatably supported by a web 55 of the casing-iii, in bearings 52, whilethe sleeve 39 is similarly supported by another web 53 of the casing, inbearings 56! The wheel 38 is free to rotate in the same direction as thewheels and 3'? but is held against rotation in the opposite direction bymeans of a one-way overrunning brake mechanism 55 which is operativelyassociated with the rear mounting sleeve 59 of the wheel 38. The brakemechanism 55 is composed of a ring 56 which is splined to the sleeve 69,an encircling ring 5i which is fastened to the web 53 of the casing, anda series of wedging rollers 58 between the rings 56 and 5?. The rollers58 are positioned in pockets 59 (see Fig. 6) which are separated byradial projections on the ring 55 and are formed between outwardlyspiraling surfaces 80 on the outer periphery of the ring 56 and theinner cylindrical surface Si of the ring 57. The rollers 58,

which are pressed in the directions in which such surfaces converge byspring-actuated follower blocks $2, serve to prevent the ring 56 fromturning backwardly while permitting it to turn forwardly with completefreedom of movement.

The blades of the turbine wheels 36, 31 and 38 are so shaped andarranged relative to each other as to cause the liquid in the system tocirculate rapidly through the passages between such blades when thedriving shaft i8, which carries the wheel 36, is rotated above an idlingspeed. The blades cause the liquid to discharge outwardly at highvelocity from the passages present between the rapidly revolving blades39 of the driving wheel 36, first against the first series of blades d6of the driven wheel 31, then against the first series of re -directingblades M of the stationary reaction wheel 36, then against the secondseries of blades 4! of the driven wheel, then against the second seriesof blades d5 of the reaction wheel, then against the third series ofblades 52 of the driven wheel, then against the third series of blades46 of the reaction wheel, then against the fourth series of blades 33 ofthe driven Wheel, and from there back again into the inner ends of thepassages between the blades 39 in the driving wheel, where the circuitis completed. The edges of the blades in each series are formed to fitcomplementarily with the edges of the blades in adjacent series, withonly enough clearance therebetween to prevent friction. The liquid iskept within the system by the application of antifriction sealing meansof any suitable description. The manner in which the liquid acts againstthe four series of blades 40, 4| 42 and 43 of t e d ive wheel and isre-directed intermediate those series by the three series of blades 44,and 46 of the stationary reaction wheel, is shown schematically in Fig.2, in which view a centrifugal type pump is used to represent the actionproduced by the blades 39 of the driving wheel. Other hydraulicconverters of this same general character are illustrated and describedin Patent No. 1,199,359.

When the driving wheel 36 is rotating slowlyat what would correspond forinstance to an idling speed of the motor-the circulation of the liquidin the system defined by the turbine wheels 36, 31 and 36 will be soslow as to have no appreciable effect on the driven Wheel 31, but whenthe driving wheel 36is speeded up the resulting velocity of the rapidlycirculated fluid will be converted into torque against the driven wheel3i and will rotate the latter under a substantial multiplication oftorque.

After the liquid system has brought the driven shaft l3 up to a speedWhere a direct drive from the shaft l8 can properly be undertaken, aslight deceleration of the driving shaft, produced by a momentary let-upof the pressure on the accelerator pedal of the motor, will result inthe driven shaft being coupled automatically to the driving shaft in apositive one-to-one drive. This is accomplished with a special clutchmechanism 63 which is located at the front end of the driven shaft 93 ina recess at the center of the rear face of the fly wheel if. The clutchmechanism 63,

which is fully explained in my copending application Serial No. 729,795,includes a collar 66 which is shiftable forwardly and rearwardly onasleeve 65, which sleeve is in turn fastened to the front end of theshaft l3. The collar 64, although movable axially, is locked against anyturning movement on the sleeve, and is provided at its rear end with aset of clutch teeth 66 for coaction with a complementary set of clutchteeth 61 on the front end of the previously described collar 20 on thedriving shaft 18. The opposed faces of the clutch teeth 66 and 61 areangularly disposed with respect to their planes of rotation (see Fig.5), which shaping serves to keep the teeth from moving into clutchedengagement with each other until such time as the speed of the drivingshaft it? has been reduced to a speed which roughly approximates that ofthe driven shaft E3.

The collar 65 of this clutch mechanism is caused to shift rearwardly bythe outward movement of a number of weights 68 which are pivoted at 69to an anchor plate 70 and are provided with inwardly extending lugs Hfor engagement with a ring 12. The ring '2 acts against one end of acoil spring 13 and the other end of the spring in turn acts resilientlyunder the pressure of the ring against a flange 74 on the rear end ofthe collar 64. When the driven shaft l3 has been accelerated by theliquid system to a point where it is rotating above a certain minimumspeed the weights 68 will be thrown out by centrifugal force and thespring 13 will be compressed, therebyforcing the angular faces of theclutch teeth 66 against the angular faces of the clutch teeth 61. Aslong as the drivingshaft l8 rotates at a much greater speed than thedriven shaft l3 the clutch teeth 61 will merely ride over the clutchteeth 66 and will not permit the latter to move into meshed associationtherewith, but as soon as any appreciable deceleration of the drivingshaft l8 takes place the teeth 66 will slip in between the teeth 61under the action of the then compressed spring and a positive one-to-onedrive will be established through the clutch mechanism from the drivingshaft to the driven shaft. The action of the clutch mechanism .8 isclearly illustrated in Fig. 3, wherein the weights 88 are shown asthrown out, the spring II as compressed, and the teeth I! as repelling ameshed association with the teeth 86 prior to the latter being permittedto move into mesh with the teeth I! upon a deceleration of the drivingshaft II. In dotted lines in the same view the clutch teeth are shown asfully meshed.

After the previously described direct drive connection has once beenestablished between the driving and driven shafts, it will continueuntil the speed of rotation of both shafts has fallen below apredetermined minimum, at which time the centrifugal force acting on theweights 88 will become insufficient to maintain the same in theiroutwardly thrown positions and they will move inwardly, allowing theclutch teeth 60 to be moved out of mesh with the teeth 61 by theexpansive action of a number of compressed coil springs 15 (see Figs. 3and 4) mounted on studs 16 carried by the plate 10.

The springs 15 serve as return springs for the weights 68 and the collar84. They are mounted .on the studs 18, and the studs 18 are riveted tothe plate 10. The ring 12 is provided at intervals with radiallyextending ears which are apertured in order to receive the studs 16. Thesprings 15 are located between these ears and washers 15', which washersare held under definite tensionby means of nuts 16' threaded on the endsof the studs. The outer portion of the ring 12 transfers the pressure ofthe springs 15 to the weights 68 by pressing against the inwardly extending lugs 1|. These springs also control the rearward movement of thecollar 64 by exert ng a pressure on it through an abutment in the formof a snap ring 64'.

This positive connection between the driving and driven shafts can alsobe terminated at any time, regardless of the speed of rotation of theshafts, by means of a ring 11 which is mounted on the collar 20 inencompassing relation to the teeth 61 and in opposition to the outerperiphery of the flange 14. The ring "is connected to an annularstamping 18 by a number of thrust pins 19 and is normally maintained ina retracted position by a compressed spring 80 which acts against thestamping 18. The stamping 18, with the ring 11, may be shifted forwardlyon the collar 20 against the action of the spring 80 by means of a fork8|, which fork is secured to a rock shaft 82 and is connected bysuitable linkage (not shown) to a conveniently located hand or footcontrol lever.

Whenever the liquid system is called into play to transmit power fromthe driving shaft l8 to the driven shaft l3 under a multiplication oftorque, the reaction wheel 38, which would rotate backwardly were it notfor the one-way brake 55, will stand still and not rotate forwardly withthe driving and driven shafts and 31. But

'as soon asthe driven shaft I 3 is coupled up with shaft 23 is locked tothe driven shaft It. To' get under way it is merely necessary toaccelerate the motor, whereupon the velocity of the rapidly circulatingliquid in the system will turnthe driven-shaft I! from the driving shaftl8 under a substantialmultiplication of torque. As soon as the drivenshaft It has attained a speed where a direct drive can advantageously beundertaken, the motor may be momentarily decelerated, whereupon thedriven shaft l3 will be automatically coupled up :with the driving shaftI 8 in a positive one-to-one drive.

After this direct drive has been established it may be discontinued atany time by shifting the throw-out ring 11 forwardly, whereupon thedrive will again take place through the liquid system under amultiplication of torque. Or the direct drive connection will bediscontinued automatically when the speed of the driving and drivenshafts falls below some predetermined minimum, by inward movement of theweights 68 and a resulting disengagement of the clutch mechanism 63.

When a reverse drive is desired the collar 24 is shifted from itsneutral position into its foremost position, in which latter positionthe shaft 23 will turn the shaft I3 backwardly through the gear train28, 29, 3!, 33 and 21. Speeding up of the motor will then effect areverse drive through the transmission under a multiplication of torque.

When the motor is brought down to an idling speed the liquid system willpermit the transmission to run free, with the result that the motor willnot stall from overload and the collar 24 need not be shifted into itsneutral positionin order to allow the driven shaft it to come to rest.

.An overrunning clutch 83 may be provided between the fiy wheel l andthe front end of the shaft I3 for the purpose of causing the motor to beturned over when the vehicle is pushed or towed. This overrunning clutchwill of course run free at all other times.

The improved transmission which forms the subject matter of the presentinvention has a wide range of application but is particularly wellsuited for use in vehicles because of its flexibility and its quietnessand smoothness of operation.

I claim:

1. In a variable speed transmission, the combination, with a drivingshaft, and a driven shaft, of a hydraulic torque converter havingdriving and driven turbine wheels which 'are connected respectively withthe driving and driven shafts for producing a multiplication of torquetherebetween, a clutch for connecting the driving and driven shaftstogether in a one-to-one drive, means for automatically throwing in theclutch upon a momentary reduction in the speed of rotation of thedriving shaft after the latter has acted through the torque converter tobring the driven shaft up to a speed where it can be handled by thedriving shaft in a one-to-one drive, means for automatically releasingthe clutch when the speed of rotation of both shafts drops below apredetermined minimum, and other manually operable means for releasingthe clutch irrespective of the speed of rotation of the shafts.

2. In combination, a torque converter comprising fluid-connected drivingand driven members, means biased in response to the speed of one of saidmembers for mechanically connecting both of said members together, andmanually operable means to overrule said first mentioned means anddisconnect said mechanical connection at the option and under thecontrol of the operator,

whereby to reestablish at will the fluid-connected drive between thedriving and driven members.

3. In combination, a torque converter comprising fluid-connected drivingand driven members, automatic means biased in response to the speed ofrotation of the driven member for mechanically connecting both of saidmembers together, and manually operable means to overrule said automaticmeans and disconnect said mechanical connection at the option and underthe control of the operator, irrespective of the speed of rotation ofthe driven member, whereby to reestablish at will the fluid-connecteddrive between the driving and driven members.

4. In combination, a torque converter comprising fluid-connected drivingand driven members, automatic means biased in response to the speed ofrotation of the driven member for mechanically connecting both or" saidmembers together, means for preventing said mechanical connection untilthe speed of the driven member is substantially equal to the speed ofthe driving member, and manually operable means to overrule saidautomatic means and disconnect said mechanical connection at the optionand under the control of the operator, irrespective of the speed ofrotation of the driven member, whereby to reestablish at "will thefluid-connected drive between the driving and driven members.

5. In a variable speed transmission, the combination, with a drivingshaft, and a driven shaft,

of a hydraulic torque converter having driving and driven turbine wheelswhich are connected respectively with the driving and driven shafts forproducing a multiplication of torque therebetween, a clutch forconnecting the driving and driven shafts together in a one-to-one drive,means for automatically throwing in the clutch upon a momentaryreduction in the speed of rotation of the driving shaft after the latterhas acted through the torque converter to bring the driven shaft up toa. speed where it can be handled by the driving shaft in a one-to-onedrive, and manually operable means for releasing the clutch irrespectiveof the speed of rotation of the shafts.

OSCAR H. BANKER.

